It is known to control access to a region by means of door access control systems. Known systems include door mounted lock modules which are connected by wires to a control interface. The interface functions as a multiplexer or concentrator and is in turn coupled to an access control unit.
Each door has associated therewith a manually operable input device such as a keypad or card reader. An individual desiring access enters a code which is forwarded by wiring to the control interface and then onto the access control unit for authorization. If the individual is authorized, the access unit signals the respective module to unlock the respective door thereby permitting access.
Alternate known systems include self-contained door mounted modules which make access decisions locally. They do not need to communicate with remote units.
Known wired units tend to be expensive and complex to install in view of a need to physically connect each door mounted module to a remote device by wiring. Self-contained systems are inconvenient when there are large numbers of access points or when there is a changing population of authorized individuals.
There continues to be a need for more cost-effective, versatile authorizing systems. Preferably such systems would incorporate non-wired remote modules while at the same time providing over-all common control and a common access data base that is usable with all devices or regions being monitored. It would also be advantageous if additional modules could be easily incorporated into such a system.